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Budzko L, Hoffa-Sobiech K, Jackowiak P, Figlerowicz M. Engineered deaminases as a key component of DNA and RNA editing tools. MOLECULAR THERAPY. NUCLEIC ACIDS 2023; 34:102062. [PMID: 38028200 PMCID: PMC10661471 DOI: 10.1016/j.omtn.2023.102062] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/01/2023]
Abstract
Over recent years, zinc-dependent deaminases have attracted increasing interest as key components of nucleic acid editing tools that can generate point mutations at specific sites in either DNA or RNA by combining a targeting module (such as a catalytically impaired CRISPR-Cas component) and an effector module (most often a deaminase). Deaminase-based molecular tools are already being utilized in a wide spectrum of therapeutic and research applications; however, their medical and biotechnological potential seems to be much greater. Recent reports indicate that the further development of nucleic acid editing systems depends largely on our ability to engineer the substrate specificity and catalytic activity of the editors themselves. In this review, we summarize the current trends and achievements in deaminase engineering. The presented data indicate that the potential of these enzymes has not yet been fully revealed or understood. Several examples show that even relatively minor changes in the structure of deaminases can give them completely new and unique properties.
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Affiliation(s)
- Lucyna Budzko
- Institute of Bioorganic Chemistry, Polish Academy of Sciences, Noskowskiego 12/14, 61-704 Poznan, Poland
| | - Karolina Hoffa-Sobiech
- Institute of Bioorganic Chemistry, Polish Academy of Sciences, Noskowskiego 12/14, 61-704 Poznan, Poland
| | - Paulina Jackowiak
- Institute of Bioorganic Chemistry, Polish Academy of Sciences, Noskowskiego 12/14, 61-704 Poznan, Poland
| | - Marek Figlerowicz
- Institute of Bioorganic Chemistry, Polish Academy of Sciences, Noskowskiego 12/14, 61-704 Poznan, Poland
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Volodina OV, Smirnikhina SA. The Choice of a Donor Molecule in Genome Editing Experiments in Animal Cells. Mol Biol 2022. [DOI: 10.1134/s002689332203013x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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Volodina OV, Anuchina AA, Zainitdinova MI, Evtushenko NA, Lavrov AV, Smirnikhina SA. Rational Design of ssODN to Correct Mutations by Gene Editing. BIOCHEMISTRY. BIOKHIMIIA 2022; 87:464-471. [PMID: 35790380 DOI: 10.1134/s0006297922050078] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/03/2021] [Revised: 04/19/2022] [Accepted: 04/19/2022] [Indexed: 06/15/2023]
Abstract
Gene editing allows to make a variety of targeted changes in genome, which can potentially be used to treat hereditary human diseases. Despite numerous studies in this area, effectiveness of gene editing methods for correcting mutations is still low, so these methods are not allowed in routine practice. It has been shown that rational design of genome editing components can significantly increase efficiency of mutation correction. In this work, we propose design of single-stranded oligodeoxyribonucleotides (ssODNs) to increase efficiency of gene editing. Using a model system to repair knocked out EGFP that is integrated into the genome of HEK293T cell culture, we have shown that only a small part of ssODN (about 20 nucleotides: from the 15th nucleotide at 3'-end to the 4th nucleotide at 5'-end), a donor molecule for repairing double-stranded DNA breaks, is integrated into the site of the break. Based on the obtained data, it is possible to rationally approach the design of ssODNs to correct mutations using CRISPR-Cas9 method for the development of gene therapy for hereditary human diseases.
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Affiliation(s)
- Olga V Volodina
- Research Centre for Medical Genetics, Moscow, 115522, Russia
| | | | | | - Nadezhda A Evtushenko
- Center for Precision Genome Editing and Genetic Technologies for Biomedicine, Pirogov Russian National Research Medical University, Moscow, 117997, Russia
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Zhang Y, Davis L, Maizels N. Pathways and signatures of mutagenesis at targeted DNA nicks. PLoS Genet 2021; 17:e1009329. [PMID: 33857147 PMCID: PMC8078790 DOI: 10.1371/journal.pgen.1009329] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2020] [Revised: 04/27/2021] [Accepted: 03/16/2021] [Indexed: 12/19/2022] Open
Abstract
Nicks are the most frequent form of DNA damage and a potential source of mutagenesis in human cells. By deep sequencing, we have identified factors and pathways that promote and limit mutagenic repair at a targeted nick in human cells. Mutations were distributed asymmetrically around the nick site. BRCA2 inhibited all categories of mutational events, including indels, SNVs and HDR. DNA2 and RPA promoted resection. DNA2 inhibited 1 bp deletions but contributed to longer deletions, as did REV7. POLQ stimulated SNVs. Parallel analysis of DSBs targeted to the same site identified similar roles for DNA2 and POLQ (but not REV7) in promoting deletions and for POLQ in stimulating SNVs. Insertions were infrequent at nicks, and most were 1 bp in length, as at DSBs. The translesion polymerase REV1 stimulated +1 insertions at one nick site but not another, illustrating the potential importance of sequence context in determining the outcome of mutagenic repair. These results highlight the potential for nicks to promote mutagenesis, especially in BRCA-deficient cells, and identify mutagenic signatures of DNA2, REV1, REV3, REV7 and POLQ.
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Affiliation(s)
- Yinbo Zhang
- Department of Immunology, University of Washington Medical School, Seattle, Washington, United States of America
| | - Luther Davis
- Department of Immunology, University of Washington Medical School, Seattle, Washington, United States of America
| | - Nancy Maizels
- Department of Immunology, University of Washington Medical School, Seattle, Washington, United States of America
- Department of Biochemistry, University of Washington Medical School, Seattle, Washington, United States of America
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Davis L, Khoo KJ, Zhang Y, Maizels N. POLQ suppresses interhomolog recombination and loss of heterozygosity at targeted DNA breaks. Proc Natl Acad Sci U S A 2020; 117:22900-22909. [PMID: 32873648 PMCID: PMC7502765 DOI: 10.1073/pnas.2008073117] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Interhomolog recombination (IHR) occurs spontaneously in somatic human cells at frequencies that are low but sufficient to ameliorate some genetic diseases caused by heterozygous mutations or autosomal dominant mutations. Here we demonstrate that DNA nicks or double-strand breaks (DSBs) targeted by CRISPR-Cas9 to both homologs can stimulate IHR and associated copy-neutral loss of heterozygosity (cnLOH) in human cells. The frequency of IHR is 10-fold lower at nicks than at DSBs, but cnLOH is evident in a greater fraction of recombinants. IHR at DSBs occurs predominantly via reciprocal end joining. At DSBs, depletion of POLQ caused a dramatic increase in IHR and in the fraction of recombinants exhibiting cnLOH, suggesting that POLQ promotes end joining in cis, which limits breaks available for recombination in trans These results define conditions that may produce cnLOH as a mutagenic signature in cancer and may, conversely, promote therapeutic correction of both compound heterozygous and dominant negative mutations associated with genetic disease.
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Affiliation(s)
- Luther Davis
- Department of Immunology, University of Washington School of Medicine, Seattle, WA 98195
| | - Kevin J Khoo
- Department of Immunology, University of Washington School of Medicine, Seattle, WA 98195
- Department of Biochemistry, University of Washington School of Medicine, Seattle, WA 98195
| | - Yinbo Zhang
- Department of Immunology, University of Washington School of Medicine, Seattle, WA 98195
| | - Nancy Maizels
- Department of Immunology, University of Washington School of Medicine, Seattle, WA 98195;
- Department of Biochemistry, University of Washington School of Medicine, Seattle, WA 98195
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Maizels N, Davis L. Initiation of homologous recombination at DNA nicks. Nucleic Acids Res 2019; 46:6962-6973. [PMID: 29986051 PMCID: PMC6101574 DOI: 10.1093/nar/gky588] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2018] [Accepted: 07/04/2018] [Indexed: 12/14/2022] Open
Abstract
Discontinuities in only a single strand of the DNA duplex occur frequently, as a result of DNA damage or as intermediates in essential nuclear processes and DNA repair. Nicks are the simplest of these lesions: they carry clean ends bearing 3′-hydroxyl groups that can undergo ligation or prime new DNA synthesis. In contrast, single-strand breaks also interrupt only one DNA strand, but they carry damaged ends that require clean-up before subsequent steps in repair. Despite their apparent simplicity, nicks can have significant consequences for genome stability. The availability of enzymes that can introduce a nick almost anywhere in a large genome now makes it possible to systematically analyze repair of nicks. Recent experiments demonstrate that nicks can initiate recombination via pathways distinct from those active at double-strand breaks (DSBs). Recombination at targeted DNA nicks can be very efficient, and because nicks are intrinsically less mutagenic than DSBs, nick-initiated gene correction is useful for genome engineering and gene therapy. This review revisits some physiological examples of recombination at nicks, and outlines experiments that have demonstrated that nicks initiate homology-directed repair by distinctive pathways, emphasizing research that has contributed to our current mechanistic understanding of recombination at nicks in mammalian cells.
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Affiliation(s)
- Nancy Maizels
- Department of Immunology, University of Washington School of Medicine, Seattle, WA 98195, USA.,Department of Biochemistry, University of Washington School of Medicine, Seattle, WA 98195, USA
| | - Luther Davis
- Department of Immunology, University of Washington School of Medicine, Seattle, WA 98195, USA
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Olson HC, Davis L, Kiianitsa K, Khoo KJ, Liu Y, Knijnenburg TA, Maizels N. Increased levels of RECQ5 shift DNA repair from canonical to alternative pathways. Nucleic Acids Res 2019; 46:9496-9509. [PMID: 30107528 PMCID: PMC6182128 DOI: 10.1093/nar/gky727] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2018] [Accepted: 08/02/2018] [Indexed: 12/11/2022] Open
Abstract
RECQ5 (RECQL5) is one of several human helicases that dissociates RAD51-DNA filaments. The gene that encodes RECQ5 is frequently amplified in human tumors, but it is not known whether amplification correlates with increased gene expression, or how increased RECQ5 levels affect DNA repair at nicks and double-strand breaks. Here, we address these questions. We show that RECQ5 gene amplification correlates with increased gene expression in human tumors, by in silico analysis of over 9000 individual tumors representing 32 tumor types in the TCGA dataset. We demonstrate that, at double-strand breaks, increased RECQ5 levels inhibited canonical homology-directed repair (HDR) by double-stranded DNA donors, phenocopying the effect of BRCA deficiency. Conversely, at nicks, increased RECQ5 levels stimulated 'alternative' HDR by single-stranded DNA donors, which is normally suppressed by RAD51; this was accompanied by stimulation of mutagenic end-joining. Even modest changes (2-fold) in RECQ5 levels caused significant dysregulation of repair, especially HDR. These results suggest that in some tumors, RECQ5 gene amplification may have profound consequences for genomic instability.
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Affiliation(s)
- Henry C Olson
- Department of Biochemistry, University of Washington, 1959 NE Pacific St., Seattle, WA 98195, USA
| | - Luther Davis
- Department of Immunology, University of Washington, 1959 NE Pacific St., Seattle, WA 98195, USA
| | - Kostantin Kiianitsa
- Department of Immunology, University of Washington, 1959 NE Pacific St., Seattle, WA 98195, USA
| | - Kevin J Khoo
- Department of Biochemistry, University of Washington, 1959 NE Pacific St., Seattle, WA 98195, USA.,Department of Immunology, University of Washington, 1959 NE Pacific St., Seattle, WA 98195, USA
| | - Yilun Liu
- Department of Cancer Genetics and Epigenetics, Beckman Research Institute, City of Hope, 1500 E. Duarte Road, Duarte, CA 91010, USA
| | - Theo A Knijnenburg
- Institute for Systems Biology, 401 Terry Ave. N., Seattle, WA 98109, USA
| | - Nancy Maizels
- Department of Biochemistry, University of Washington, 1959 NE Pacific St., Seattle, WA 98195, USA.,Department of Immunology, University of Washington, 1959 NE Pacific St., Seattle, WA 98195, USA
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Rees HA, Yeh WH, Liu DR. Development of hRad51-Cas9 nickase fusions that mediate HDR without double-stranded breaks. Nat Commun 2019; 10:2212. [PMID: 31101808 PMCID: PMC6525190 DOI: 10.1038/s41467-019-09983-4] [Citation(s) in RCA: 64] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2019] [Accepted: 04/04/2019] [Indexed: 12/20/2022] Open
Abstract
In mammalian cells, double-stranded DNA breaks (DSBs) are preferentially repaired through end-joining processes that generally lead to mixtures of insertions and deletions (indels) or other rearrangements at the cleavage site. In the presence of homologous DNA, homology-directed repair (HDR) can generate specific mutations, albeit typically with modest efficiency and a low ratio of HDR products:indels. Here, we develop hRad51 mutants fused to Cas9(D10A) nickase (RDN) that mediate HDR while minimizing indels. We use RDN to install disease-associated point mutations in HEK293T cells with comparable or better efficiency than Cas9 nuclease and a 2.7-to-53-fold higher ratio of desired HDR product:undesired byproducts. Across five different human cell types, RDN variants generally result in higher HDR:indel ratios and lower off-target activity than Cas9 nuclease, although HDR efficiencies remain strongly site- and cell type-dependent. RDN variants provide precision editing options in cell types amenable to HDR, especially when byproducts of DSBs must be minimized.
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Affiliation(s)
- Holly A Rees
- Merkin Institute of Transformative Technologies in Healthcare, Broad Institute of Harvard and MIT, Cambridge, MA, 02142, USA
- Howard Hughes Medical Institute, Harvard University, Cambridge, MA, 02142, USA
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA, 02138, USA
| | - Wei-Hsi Yeh
- Merkin Institute of Transformative Technologies in Healthcare, Broad Institute of Harvard and MIT, Cambridge, MA, 02142, USA
- Howard Hughes Medical Institute, Harvard University, Cambridge, MA, 02142, USA
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA, 02138, USA
- Program in Speech and Hearing Bioscience and Technology, Harvard Medical School, Boston, MA, 02115, USA
| | - David R Liu
- Merkin Institute of Transformative Technologies in Healthcare, Broad Institute of Harvard and MIT, Cambridge, MA, 02142, USA.
- Howard Hughes Medical Institute, Harvard University, Cambridge, MA, 02142, USA.
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA, 02138, USA.
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